Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

All pass op-amp based filter with upwards sloping phase shift chart

Status
Not open for further replies.
Y

yishaika

Newbie
Joined
Jul 31, 2017
Messages
2
Helped
0
Reputation
0
Reaction score
0
Trophy points
1
Activity points
20
I need an All-pass first order filter that is opposite (complementary?) to the usual implementation. I need it to have a phase shift of -180 degrees when approaching DC, -90 degrees at w0, and 0 degrees going to high frequencies.
All normal implementation I found have decreasing phase shift (from +180 to 0 degrees, or from 0 degrees to -180 degrees). This is required to compensate for another filter operating on a wide band (3KHz to 40KHz) signal. Is such an analog filter possible?
 

Thank you, but this won't work for me. First thing I tried. Also exchanged r and c.. You have a phase shift of 180 degrees at DC going down through 90 deg (leading) to 0 deg at very high frequencies. I need a phase shift of -180 deg at DC, going through -90 degrees (lagging) to 0 deg at high frequencies.
 

As far as I'm aware off, you can't implement analog all-pass filters with leading phase/frequency characteristic. It's of course possible with digital filters.
 

Here's my LTspice simulation.
Looks to me like it goes from -180° to -90° to 0°.
Isn't that what you wanted?

Capture.PNG
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top